Benefits of Levothyroxine Replacement Therapy on Nonalcoholic Fatty Liver Disease in Subclinical Hypothyroidism Patients

Objectives . To evaluate the effect of levothyroxine (LT 4 ) replacement therapy on nonalcoholic fatty liver disease (NAFLD) in subclinical hypothyroidism (SCH) patients. Methods . This study was a post hoc analysis of a randomized controlled trial and involved 33 significant and 330 mild SCH patients. All of the significant SCH patients received LT 4 supplement. The mild SCH patients were grouped as LT 4 treated or not. After 15 months of follow-up, prevalence of NAFLD in each group was reevaluated. Subgroup analysis was conducted in mild SCH patients with dyslipidemia. Results . After treatment with LT 4 , the prevalence of NAFLD in significant SCH patients reduced from 48.5% to 24.2% (p=0.041). In mild SCH patients, prevalence of NAFLD and serum alanine aminotransferase (ALT) was not significantly affected by LT 4 supplementation. Nonetheless, mild SCH patients with dyslipidemia who received LT 4 treatment experienced decreases in the prevalence of NAFLD and serum ALT levels (p<0.05for both). In contrast, these parameters remained comparably stable in patients who were not treated. Conclusion . LT 4 supplementation has benefits on NAFLD in significant SCH patients or mild SCH patients with dyslipidemia. For NAFLD patients with SCH, appropriate supplementation of LT 4 may be an effective means of controlling NAFLD. The original trial was registered with ClinicalTrials.gov ( NCT01848171 ).